> Ok. I lied. Removing multiplexing did not fix the problem.
> 
> It's strange, I _know_ my network is clean, I know my backup policies should
> be fine.. 
> 
> I'm still concerned about the busy percentage of rmt/1 v.s. Rmt/0.

I didn't reply initially because it appeared that you had fixed it.

I too would be very suspicious of those iostat figures.  To me the high
busy alongside very low throughput screams drive problems.  Multiplexing
shouldn't be affecting that.

If at all possible, I'd try to replicate the error by doing some drive
testing outside of NBU.  

Down the drive, load a scratch tape, then get busy with 'dd' or
something.  Can you make it behave similarly?  If so, I'd make it my
number one suspect.
-- 
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
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